Winched rod pump apparatus and method

ABSTRACT

An apparatus and method for pumping fluids with a winched rod pumping apparatus for imparting reciprocating substantially vertical motion to a rod of a sucker-rod pump. A winched rod pumping apparatus, includes a motor driven winch drum and cable mechanical actuator arrangement. The winch drum and cable mechanical actuator arrangement includes a substantially vertically moveable member attached to the rod of the sucker-rod pump. The vertical moveable member is coupled to one end of the cable and the other end of the cable is coupled to the winch drum. The winch drum is configured to rotate in one direction to index the rod in a vertical up direction and to index the rod in a vertical down direction, with the winch drum completing at least one full rotation and the rod completing one cycle. The rod cycle is in relation to a pumping cycle for the down hole pump.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims priority to U.S. Provisional Application No. 61/788,123, filed Mar. 15, 2013, incorporated herein in its entirety, by this reference.

FIELD OF THE INVENTION

This invention relates to pumping of fluids, such as water and/or hydrocarbons, from subterranean formations or reservoirs, and more particularly to a pumping apparatus and method for use in such pumping applications.

BACKGROUND OF THE INVENTION

For many years, the familiar “horsehead” walking-beam type mechanism has been used for pumping fluids such as water and/or oil from subterranean formations. As discussed at length in commonly assigned co-pending U.S. Pat. No. 8,152,492, titled “Linear Rod Pump Apparatus and Method,” by Beck et al., conventional walking beam apparatuses have a number of disadvantages, not the least of which is their large size. In addition, performance of the walking beam pump apparatus is largely a function of the design in connection of a number of mechanical parts, which include massive counter-weights and complex drive mechanisms which are difficult to control for obtaining maximum pumping efficiency or to compensate for changes in the condition of the well over time.

Also, for potential well sites in very remote locations, and particularly in locations without access to a power grid and no practical road access for regularly servicing a pumping apparatus or a motor generator, batteries, or other traditional stand-alone power source for a pumping apparatus, it has heretofore been impractical, and in some cases impossible, to utilize a conventional walking-beam apparatus or other known types of prior pumping apparatuses and methods. As a result, potentially valuable energy resources have remained untapped.

Although the linear rod pump apparatus and methods, disclosed in the above-referenced '492 to Beck, provide significant improvement over other prior pumping apparatuses and methods in many pumping applications, the frequently reversing motor utilized in the linear rod pump apparatus and methods disclosed in Beck '492 may not be desirable in some pumping applications. For such applications, another type of apparatus and method which could operate with less reversing of the motor might prove to be more desirable.

The apparatus of the present disclosure must also be of construction which is both durable and long lasting, and it should also require little or no maintenance to be provided by the user throughout its operating lifetime. In order to enhance the market appeal of the apparatus of the present disclosure, it should also be of inexpensive construction to thereby afford it the broadest possible market. Finally, it is also an objective that all of the aforesaid advantages and objectives be achieved without incurring any substantial relative disadvantage.

SUMMARY OF THE INVENTION

This invention provides an improved apparatus and method for pumping fluids, such as water and/or hydrocarbons, from a subterranean formation or reservoir, through use of a winched rod pumping apparatus for imparting reciprocating substantially vertical motion to a rod of a sucker-rod pump having a pump stroke. A winched rod pumping apparatus, according to the invention, includes a motor driven winch drum and cable mechanical actuator arrangement. The winch drum and cable mechanical actuator arrangement includes a substantially vertically moveable member attached to the rod of the sucker-rod pump for imparting and controlling vertical motion of the rod of the sucker-rod pump. The vertical moveable member is coupled to one end of the cable and the other end of the cable is coupled to the winch drum.

The cranked mechanical actuator arrangement may include a frame having a base thereof which is adapted for attachment to the wellhead of the well. The frame further includes at least two pulleys configured to receive and guide the cable. The vertically moveable member is coupled to the cable for substantially linear reciprocating vertical movement.

There is provided a winch rod pumping apparatus to impart reciprocating vertical motion to a rod of a sucker-rod pump having a pump stroke. The rod is coupled to a rod string of a well which in turn is coupled to a sucker pump down hole from the well head. The winch rod pumping apparatus includes a vertical moving member coupled to the rod. A cable, having two ends, with one end coupled to the vertical moving member. A motor is coupled to a winch drum with one end of the cable operatively coupled to the winch drum. The winch drum is configured to rotate in one direction to index the rod in a vertical up direction and to index the rod in a vertical down direction, with the winch drum completing at least one full rotation and the rod completing one cycle. The rod cycle is in relation to a pumping cycle for the down hole pump.

The winch rod pumping apparatus includes a motor drive, a gear box and a controller coupled to the motor for operating the motor in a substantially constant input power operational mode. In another embodiment, the winch rod pumping apparatus includes an inertial flywheel coupled to the winch drum or the motor, with the inertial flywheel configured to store kinetic energy from the winch drum during a portion of the winch drum rotation and to impart the stored energy to the winch drum during another portion of the winch drum rotation. The inertial flywheel may be coupled to the motor, may be coupled externally to the winch drum or may be coupled internally to the winch drum.

In another embodiment, the winch rod pumping apparatus includes a mechanical reversal mechanism coupled to the winch drum with the mechanical reversal mechanism configured to allow the winch drum to continue moving in one direction during both the vertical up and vertical down direction of the rod.

In another embodiment, the winch rod pumping apparatus includes a second cable having two ends with one end coupled to the winch drum and the other end coupled to the vertical moving member. Each cable end is coupled to the vertical moving member proximate an end of the vertical moving member. In another embodiment, each cable of the two cables includes two separate portions, with each portion composed of one of a metal wire, a synthetic fiber and a combination of metal wire and synthetic fiber.

The winch drum includes a drum portion defining a circumferential channel, with each channel configured to receive the cable as the winch drum rotates about a winch drum axis. Each winch drum portion includes a cable clamp configured to engage one end of the cable. The cable clamp is configured to rotate within a socket defined in the drum portion along the axis parallel to the winch drum axis. In another embodiment, the winch rod pump apparatus includes at least one additional drum portion for each cable coupled to the winch drum. The winch drum is configured to complete at least one additional rotation during one cycle of the rod. In another embodiment, the winch drum will make multiple rotations during one cycle of the rod in relation to the depth of the down hole pump.

In another embodiment two winch drums and multiple cables are coupled to two motor and gear boxes. Such arrangement is disposed proximate the well head.

The apparatus of the present invention is of a construction which is both durable and long lasting, and which will require little or no maintenance to be provided by the user throughout its operating lifetime. Finally, all of the aforesaid advantages and objectives are achieved without incurring any substantial relative disadvantage.

DESCRIPTION OF THE DRAWINGS

These and other advantages of the present disclosure are best understood with reference to the drawings, in which:

FIG. 1 is an illustration of a conventional walking beam pump system, also referred to as a horse-head pump.

FIG. 2A is a perspective illustration of an exemplary embodiment of a winch rod pump apparatus with a pair of winch drums proximate a well head, and pulleys proximate a top portion of the apparatus structure, with cables coupled to the winch drums, extending on the pulleys, and coupled to a vertical moving member.

FIG. 2B is an end view of the winch rod pump apparatus illustrates in FIG. 2A.

FIG. 2C is a side view of the winch rod pump apparatus illustrated in FIG. 2A.

FIG. 3A is a perspective illustration of an exemplary embodiment of a winch rod pump apparatus with a pair of winch drums proximate a top portion of the apparatus with directional pulley sets coupled to the apparatus structure, with cables coupled to the winch drums, extending on the pulleys, and coupled to a vertical moving member.

FIG. 3B is an end view of the winch rod pump apparatus illustrated in FIG. 3A.

FIG. 3C is a side view of the winch rod pump apparatus illustrated in FIG. 3A.

FIGS. 4A-C are illustrations of the winch rod pump apparatus illustrated in FIGS. 2A-C, configured in a low-profile configuration.

FIG. 5 is a perspective, exploded view of an exemplary embodiment of a modular winch drum assembly used in the winch rod pumps illustrated in FIGS. 2A-4C, with an exemplary embodiment of a cable clamp configured to engage one end of the cable and with the cable clamp coupled to a drum portion and further configured to rotate in a socket coupled to the drum portion along an axis parallel to a winch drum axis, with an inertia flywheel mechanism included with the winch drum assembly.

FIG. 6A is a side view of an exemplary embodiment of the winch drum illustrated in FIG. 5.

FIGS. 6B and 6C are end views of the winch drum illustrated in FIG. 5.

FIGS. 7A-7C are perspective views of an exemplary embodiment of a winch drum illustrating a two cable arrangement and multiple revolutions wraps of the cables in two directions of the winch drum and cables rotations.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In addition to the “horsehead” walking beam 102 type of mechanism used for pumping fluids, other pumping mechanisms are used. For example, hydraulic cylinders are used instead of conventional horse-head pumping units. Hydraulic cylinder systems are complex, noisy, and prone to hydraulic leaks and are generally inefficient.

This disclosure eliminates many of the disadvantages of the aforementioned apparatuses by providing a relatively small, lightweight, easy to install unit that does not require counterweights, providing a system that is more economical and naturally more efficient during changing well conditions. Referring to FIGS. 1-7C inclusive, there is disclosed a winched rod pumping system 106 and method configured to include a winched rod pump having a mechanical winch 146 and cabling 124, 130 drive arrangement, adapted for attachment to a pumping mechanism, such as the pump rod 110 at the top of a rod string 114 in a hydrocarbon well 100.

Several embodiments of the winch drum 146 and associated cabling 124, 130 are adapted for connection to, and movement with, the pump rod 110. The winch drum 146 rotates as the cabling translates, and is driven by a reversible motor 140 for affecting the up and down reciprocating motion of the cabling 124, 130 and pump rod 110, including a mechanical reversal mechanism 170 at the bottom of the stroke, thereby eliminating the need for motor 140 reversal at the bottom of the stroke 108. The system also provides an inertial flywheel 164 sink for storing down-stroke kinetic energy for retrieval upon the next upstroke, consequently increasing system efficiency without the need for large, heavy counterweights or braking mechanisms, neither electrical nor mechanical. In some configurations, multiple winch drums 146 and motors 140 are coupled to cables 124, 130 and the vertical moving member 122 to operate the downhole pump.

The system is configured to provide a smaller footprint for space restricted installations such as infill drilling sites and urban settings, and its compactness allows for an enclosed, safer pumping system with no exposed pinch points and moving linkages. Further, in one embodiment the design coupled with a recessed wellhead allows for an extremely low height profile (See FIGS. 4A-4C) while still providing a long stroke length, necessary for deep wells with surface height restrictions such as overhead irrigation systems. Furthermore, the design elegantly employs an inertial (flywheel) mechanism 164 for storing generated energy to be later used in motoring, increasing energy efficiency. The pumping system uses less raw material in its construction, including a much smaller gearbox 142 mechanism, a conservation-minded and lower cost solution to a conventional pumping system.

On a winched rod pump system 106, the reciprocating action of the rod string 114 is accomplished by the rotation of the winch drum 146 assembly, which translates a flexible cable 124, such as for example a wire rope, a metal wire, a synthetic fiber rope, and a combination of any such cables, which is in turn connected to a traditional “bridle” type coupling 112 to the pump rod 110, also referred to as a polished rod 110. The winch drum 146 is rotated in one direction to cycle the polished rod down and up, and then in the opposite direction to cycle the polished rod down and up. Such motion operates the down hole sucker pump.

The winch drum 146 includes a mechanical reversal mechanism 170 at the bottom of the stroke, allowing the winch drum 146 to continue moving in the same direction through the bottom of stroke as the pump rod 110 string 114 reverses direction. At the top of stroke, the drum 146 reverses direction to transition the rod string back to the down-stroke. In this way, the rod string 114 will make one complete cycle, from top to bottom to top, with one drum multiple rotation, after which the drum will reverse rotation direction. In some configurations the winch drum 146 will make multiple revolutions, wrapping the cable 124, 130 several times around the drum 146, in one direction, in relation to the down hole pump depth. Upon the drum 146 direction reversing, the rod string 114 will make another complete cycle, from top to bottom to top. Consequently, the rotation direction of the drum 146 alternates once with every full cycle of the rod string 114.

In conjunction with a power management controller scheme, the reversal mechanism 170 at the bottom of stroke (with fixed drum rotation) provides an advantage to drum reversal (through motor direction reversal) inasmuch as it allows the kinetic energy of the down-stroke to be stored in an inertial flywheel 164 and subsequently retrieved during the following upstroke, thereby increasing energy efficiency of the system as well as eliminating the need for counter-weights for energy efficiency purposes.

In certain embodiments, it may be desirable to reduce the loading on a single apparatus. In such cases, two or more separate assemblies may be coupled to the polished rod 110 with each assembly 116 supporting a substantially equal portion of the load. In some embodiments, this may be accomplished by having otherwise separate assemblies sharing a common bridle.

For purposes of this disclosure, the term “coupled” means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or the two components and any additional member being attached to one another. Such adjoining may be permanent in nature or alternatively be removable or releasable in nature.

Although the foregoing description of the present mechanism has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the mechanism as described herein may be made, none of which depart from the spirit or scope of the present disclosure. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the mechanism and its practical application to thereby enable one of ordinary skill in the art to utilize the disclosure in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present disclosure as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. 

What is claimed is:
 1. A winch rod pumping apparatus to impart reciprocating vertical motion to a rod of a sucker-rod pump having a pump stroke, with the rod coupled to a rod string of a well, the apparatus comprising: a vertical moving member coupled to the rod; a cable having two ends with one end coupled to the vertical moving member; and a motor coupled to a winch drum with one end of the cable operatively coupled to the winch drum, the winch drum configured to rotate in one direction to index the rod in a vertical up direction and to index the rod in a vertical down direction, with the winch drum completing at least one full rotation and the rod completing one cycle.
 2. The winch rod pumping apparatus of claim 1, further comprising: a motor drive and controller coupled to the motor for operating the motor in a substantially constant input power operational mode.
 3. The winch rod pumping apparatus of claim 1, further comprising: an inertial flywheel coupled to the winch drum, with the inertial flywheel configured to store kinetic energy from the winch drum during a portion of the winch drum rotation and to impart the stored energy to the winch drum during another portion of the winch drum rotation.
 4. The winch rod pumping apparatus of claim 1, further comprising a mechanical reversal mechanism coupled to the winch drum with the mechanical reversal mechanism configured to allow the winch drum to continue moving in one direction during both the vertical up and vertical down direction of the rod.
 5. The winch rod pumping apparatus of claim 1, further comprising a second cable having two ends with one end coupled to the winch drum and the other end coupled to the vertical moving member with each cable end coupled to the vertical moving member proximate an end of the vertical moving member.
 6. The winch rod pumping apparatus of claim 1 or claim 5, with each cable including two separate portions, with each portion composed of one of a metal wire, a synthetic fiber, and a combination of metal wire and synthetic fiber.
 7. The winch rod pumping apparatus of claim 1, further comprising the winch drum includes a drum portion defining circumferential channel, with each channel configured to receive the cable as the winch drum rotates about a winch drum axis.
 8. The winch rod pumping apparatus of claim 7, with each drum portion including a cable clamp configured to engage the one end of the cable, with the cable clamp configured to rotate within a socket defined in the drum portion, along an axis parallel to the winch drum axis.
 9. The winch rod pumping apparatus of claim 7, including at least one additional drum portion for each cable coupled to the winch drum.
 10. The winch rod pumping apparatus of claim 1, wherein the winch drum is configured to complete at least one additional rotation during the one cycle of the rod.
 11. A method to impart reciprocating vertical motion to a sucker rod pump at a well head, with the pump including a pump rod, the method comprising: coupling a vertical moving member to the pump rod; installing a motor and gear box on a support structure proximate the well head; coupling a winch drum to the gear box; mounting a pulley to the support structure and aligning the pulley with the winch drum; coupling one end of a cable to the vertical moving member and another end of the cable operatively to the winch drum; and configuring the winch drum to rotate in one direction to index the pump rod in a vertical up direction and to index the pump rod in a vertical down direction, with the winch drum completing at least one full rotation and the pump rod completing a cycle.
 12. The method of claim 11, further comprising: configuring the winch drum to store kinetic energy of the down-stroke of the pump rod in an inertial flywheel coupled to the winch drum and using the stored energy during the following up-stroke of the pump rod cycle.
 13. The method of claim 11, further comprising: coupling a second winch drum to the gear box; coupling a second pulley to the support structure and aligning the pulley with the winch drum a spaced distance from the other pulley; and coupling a second cable to the second winch drum and the vertical moving member.
 14. The method of claim 11 or claim 12, with each cable including two separate portions, with each portion composed of one of a metal wire, a synthetic fiber, and a combination of metal wire and synthetic wire. 